This invention pertains to thermographic recording using laser radiation, and to a system of forming holes in data cards for storage and retrieval of information.
Previously, an apparatus for data signal recording with a laser beam was described in U.S. Pat. No. 3,256,524 issued June 14, 1966 to N. L. Stauffer. It employed a thin film coated with aluminum or other materials of lower heat of vaporization as the recording medium in which holes were produced by laser irradiation. A similar application has been described in Scientific Research, July 21, 1969, page 27, using data cards for a mass memory system. In the latter process, digital information is recorded by burning holes through plastic cards upon irradiation with focused laser radiation.
A system for recording data employing a film having a black coating and a laser was described in U.S. Pat. No. 3,314,073 issued Apr. 11, 1967 to C. H. Becker. The coating consisted of fully developed gelatin photographic emulsion or dyed gelatin.